Canine Liver

Canine liver and cavitary hepatic lesions usually are cysts or abscesses, although occasionally large neoplastic lesions such as hemangiomas and adenomas cavitate. Canine liver abscesses are localized collections of pus in the hepatic parenchyma. Canine liver cysts are closed, fluid filled sacs, lined by secretory epithelium.

Canine hepatic abscesses are rare and usually associated with extrahepatic infection (i.e., ascending biliary tract infections, hematogenous infection via the portal vein or hepatic artery, or direct extensions from areas adjacent to the liver), hepatic trauma (i.e., surgical biopsy, penetrating wounds, or blunt trauma), or neoplasia. Despite the normal presence of bacteria in the dog liver, hepatic abscesses seldom occur. This may be related to a well-developed local defense system provided by the liver'S rich blood supply and the phagocytic ability of reticuloendothial cells.

Canine liver abscesses are most often recognized as a complication in puppies and usually are diagnosed at necropsy. Canine diabetes mellitus has been associated with liver abscesses. The organisms most often isolated from hepatic abscesses in dogs include E. coli and Chlostridium spp. Small abscesses may not cause clinical signs and may resorb without therapy.

Canine liver cysts usually are incidental findings, although in rare cases they become large enough to interfere with the normal functioning of adjacent organs. A single hepatic cyst may be noted, or several cysts may be present in the same or different lobes. If hepatic cysts are present in an animal with clinical evidence of hepatic dysfunction, liver biopsy often is warranted to determine the cause.